This invention is directed to an improvement in grinding apparatus which is combined with a fan to assure flow of material from the inlet to the outlet of the housing in which material grinding apparatus is mounted.
Crushing and grinding machines of the character disclosed in U.S. Pat. No. 4,706,898 of Nov. 17, 1987 are typical of apparatus that requires excessive power consumption due to the high resistance offered by the outlet grate which presents surfaces which block the free flow of material after being ground or processed.
Typical in the art is material reducing apparatus having pivoted or free swinging hammers on a driven rotor mounted in a housing having grate structure that restricts the outflow of reduced material. Apparatus of this character can be found in such U.S. Pat. Nos. as 1,301,316 of Apr. 22, 1919 or 1,751,009 of Mar. 18, 1930, or 3,610,543 of Oct. 5, 1971 or 4,009,836 of Mar. 1, 1977. In such apparatus the pivoted hammers are quite capable of damaging the drive shaft on which they are mounted by the result of hammer rebound when striking a large heavy article.
Apparatus of the foregoing character is found to be difficult to reduce light weight or fluffy material which is due in the most part, to the resistance of the grate surface which causes such material to bypass the grate and return to the material receiving side of the rotor.
The foregoing objections in the prior art are substantially overcome by a unique combination of pivoting hammers that are free to rotate, or even rebound, but do not strike the shaft on which they are mounted, a grate structure in the outlet that greatly reduces resistance to the outflow of reduced materials, and fan means moving with the hammers to propel the reduced material through the outlet, thereby avoiding the need for an external fan.
Further objects of this invention will be set forth in greater detail in the accompanying drawing wherein:
FIG. 1 is a vertical sectional view of the grinding apparatus embodying the present invention, and
FIG. 2 is a fragmentary sectional view to illustrate the characteristics of the hammer and fan rotor, as seen along line 2--2 in FIG. 1.